Iron-silver batteries are well known in the art, and taught by Brown in U.S. Pat. No. 4,078,125. These batteries, while displaying outstanding high energy densities, have their own unique problems. In the typical zinc-silver cell, the negative zinc electrode is the life limiting component, but in the iron-silver cell, the positive silver electrode which has a solubility problem is the primary life limiting component.
Silver electrodes have a limited solubility in KOH electrolyte, and are most soluble near the end of charge when the highest positive electrode potentials are achieved. This limited solubility results in the transference of metallic silver to the other parts of the cell, such as the separators and anode. The result of this silver solubility can be eventual cell failure due to excessive leakage current, or an internal short circuit.
Iron-silver batteries, using negative electrodes made from fiber metal current collectors and Fe.sub.3 O.sub.4 pasted active material, also require an extended "formation" period, requiring several charge-discharge cycles before full design capacity is achieved, and upon extended cycling, some shedding of the active material from the iron electrode may occur.